Introduction - Welcome to pocketmod!

Hello stranger, I’ve heard you’re here to design your own pocketmod - a USB dongle for your laptop (or PC) which provides some sort of functionality. Before you can start, I’ve got some notes for you.
First of all we need to make sure, the project is actually made by you and how long it took you to make.

Timetracking

For the hardware (pcb, case, assembly) use Lapse to make a timelapse of your work and provide a short journal by writing about 2-3 sentences about what you did after every session in the journal book so that others can understand your work.
For coding use Hackatime to track your working time.

Second, lets define what a pocketmod can be.

Requirements - what should my pocketmod have?

Plugs into an USB port (A, B or C)
Provides some kind of functionality
If it has a programmable MCU either provide a self-written firmware or tells us which other firmware you want to flash on it (like Meshtastic, pico-fido, etc.)
If your pocketmod requires a special software on the host PC (i.e. for sending system data which is displayed on a display or receiving some sort of inputs) also provide a version of this software
Optional: Design a case, get it 3d printed by #printing-league

You may ask yourself, what you’ll get for it

Prizes

When submitting your project, you’ll receive a grant at 4.5$ per working hour to get it manufactured (for example from JLCPCB), after you’ve shipped your project, the remaining money on the grant card will be converted to sticks at the rate of 1$ = 1 sticks. Additionally you can earn bonus sticks by participating in the community, helping others or reaching certain milestones in your design. The sticks can be redemed in the shop to get tools useful for your project and other prizes. If you need more money to get it manufactured, you can try adding additional features to your pcb or firmware/software for more hours. If it should be absolutely not possible, dm @leost on slack and we try to work something out.

The process

design your pocketmod (maybe + firmware / case) + track your time
submit your project
receive a manufacturing grant (4.5$/h) + get it manufactured
ship your project by uploading a short clip of it build
get prizes
(repeat)

Like often in life, we also have certain

Rules

be nice to everyone, follow the Code of Conduct
no AI slop, you can totally use AI for asking questions or help, but we will reject projects which are just completely made by AI with no human effort

Guides

If you’re new to pcb design, head over to our [beginner tutorial](FIRST PCB LINK). For additional tips & resources, have a look on the [resources page](RESOURCES LINK).

So everything clear? If not head to the FAQ section, ask in #pocketmod or DM me (@leost on slack).

Welcome to pcb design

Note: This guide is intended for participants, with none to little experience in pcb/ hardware design. If you just want to get started, check out our quick start guide.

Hi, so you want to make your own pc gadget for pocketmod, nicee. Today we’re going to design a little light for your keyboard, while I’ll show you the basics of pcb design.

Set up

In this tutorial we’ll be using Kicad, an open source pcb design tool which is free to use and really great. So first of all download kicad from their website and install it. After the installation, you should see this homescreen:

From here we will start by creating a new project by clicking on File -> New Project selecting the default template and the location to store the project.

With this done, you see that kicad has already created two files within our project, a .kicad_sch , for the schematic and a .kicad_pcb for the pcb design.

Drawing the schematic

The schematic is what defines all the connections of your pcb, so let’s start with it. First open the schematic editor by clicking on the schematics button.

At first the UI may seems a bit overwhelming, but it’s structured very logically.

On the right side you can find the tools for editing your schematic. Press a to open the symbol insert window (a symbol is the representation of a component in your schematic). Here you find a list of components, search for USB and select a vertical usb a plug.

You can see that the symbol you just placed exposes the connectors, the component has, as little red lines.

Additionally to the connector, our light also needs something to shine, so let’s add a few leds.

As our leds only need about 3v and the USB will give us 5v of power we need some way to get this power down. One simple to do this is by just placing some strong resistors in front of our leds. To calculate this, we can use this simple formular:
R = (Vusb - Vled) / Iled
For our test leds with 3v and 25mA (=0.025 A) this comes down to R = (5-2) / 0,025 = 120 Ω. So let’s add the resistors, one for each LED.

Connect them to front of the LEDs, then open the symbol properties by double clicking on the resistor symbol. Under value enter the 120 Ω we calculated before and press enter. Repeat this for every resistor.

Now your schematic should look something like this, if you want to rotate a symbol you can do that by selecting it and pressing r.

As we’ve placed all the symbols we need, we can now wire them up. In the right sightbar select the wire tool (5th icon from the top) and place wires like this.

Congrats, you’ve just created your first schematic🎉. So lets turn it into a pcb.

Designing the pcb

Now we have to tell Kicad how the symbols in our schematic look on the pcb. That’s done using so called footprints, they tell kicad how to connector pads or holes for the component look like.
Lets start by opening the footprint assignment tool, with this button in the top bar.

In the footprint assignment tool, assign the footprints by selecting a symbol in your schematic from the middle and then double clicking on the according footprint on the right. Assign the footprints like this and then press ok.

As kicad now knows how the components on our pcb will look, we can switch to the pcb design tool, by clicking on this button:

In the design tool, use the “Update PCB from schematic” button to automatically import the components from the schematic on your pcb.

Place the components on the pcb by clicking and arrange them like this (drag and drop). The way you arrange your components here will determine how they will be placed on the pcb. Make sure to leave enough space between the usb plug on the LEDs to fit on the side of your pcb or laptop.

Then we can go on placing the wires on the pcb. Select the routing tool from the right side bar.

The lines you can see in light blue show you which components should be connected together, go ahead and wire this connections together. It should look something like this:

Now we just have to tell Kicad what size our the pcb should have in the end. You can do that by selecting the edge.cuts layer in the right sidebar and then drawing a rectangle around your components.

You can click the 3d viewer icon to see your pcb in 3d.

Congrats, you’ve just designed your first pcb🎉.

Next steps

You’ve just made a simple USB powered keyboard light, but of course there’s a ton of other cool stuff out there.
For your pocketmod I would recommend you should start by defining a basic feature it should have, build it and then add more features, rather than starting with a huge mountain of requirements and no idea where to start.
If you still need some inspiration, use the idea generator on the pocketmod website or look at submissions in the gallery. You can also have a look at their schematics to understand what the creators exactly did.

For some additional tips and tricks, look in the additional resources tab.

Additional resources

A collection of stuff to help you in the design process.

Overall

Hack Club Hardware docs by Alex Ren

Tutorials / Guides

Official Kicad documentation

Tools / Software

Kicad for pcb design
Onshape for CAD design
easyeda2kicad a usefull tool to quickly get the symbols/footprints of LCSC / JLCPCB parts into kicad, can make mistakes tho, so double check the footprints before ordering
kicad-jlcpcb-tools a kicad plugin for generating correct production data for JLCPCB